On 3/6/2015 2:46 AM, AndyW wrote:
On 05/03/2015 23:04, gareth wrote:
"Iain Young, G7III" wrote in message
...

An awful lot of evidence by citing off-the-shelf solutions for both
the hardware and the software of SDR.

It depends where you draw the line.
I have a DVB dongle that I use under linux.
I use pre-written drivers and a waterfall code module but the rest of
the code is self-written by me in c++ and python with some java 2D stuff
for the pretty front end and logging and analysis (largely because I
prefer the collections interface in Java over c++ for massive data
handling).

It is certainly homebrew because the amount of time and effort I spent
in writing to code (and time to learn python on codeacademy - good site
BTW) was probably longer than I have spent designing and building hardware.

Your mileage may vary....

Andy


I didn't know about these things. Pretty amazing. A UHF/VHF tuner for
under $10 on eBay. Which one do you have?

--

Rick

On 06/03/2015 13:32, Ian Jackson wrote:
In message , Charlie
writes
On Thu, 05 Mar 2015 22:01:39 +0000, Iain Young, G7III wrote:

A HF upverter added to the front end, and you are all set.

Very simple project, a cheap DIL crystal oscillator around 50MHz,
passive mixer with the ports switched around and you have a LF/MF/HF RX
from DC. Some front end filtering and Bob's your unc.

My first 2m QSO was made with a CB set feeding into a home-made
double-balanced diode mixer, and an ancient sig gen as the LO on 118 (or
maybe 177) MHz.

An interesting variation on the typical 28MHz 2m transverter. I'm a
bit surprised there were suitable CB sets around at the time I would
expect you to be starting our on 2m.

I've never been keen on transverters myself. I still have a Microwave
Modules 2m 70 cm transverter somewhere, they were very popular in the
early 1980s or so. It worked well enough it was the need to keep
swapping things around I didn't like. Fine if you dedicate a radio for
use with the transverter but, in those days, I didn't have the luxury of
suitable radios to do that.

"Charlie" wrote in message
...
On Fri, 06 Mar 2015 07:45:15 +0000, Jim GM4DHJ ... wrote:

He can see exactly what brian is doing....what a man ! ......

I've come to the conclusion it's compulsive, ditto the boy wonder's
behaviour across usenet.


perhaps electric shock treatment would help? .......we could lend a hand

On 06/03/2015 15:07, rickman wrote:
On 3/6/2015 2:46 AM, AndyW wrote:
On 05/03/2015 23:04, gareth wrote:
"Iain Young, G7III" wrote in message
...

An awful lot of evidence by citing off-the-shelf solutions for both
the hardware and the software of SDR.

It depends where you draw the line.
I have a DVB dongle that I use under linux.
I use pre-written drivers and a waterfall code module but the rest of
the code is self-written by me in c++ and python with some java 2D stuff
for the pretty front end and logging and analysis (largely because I
prefer the collections interface in Java over c++ for massive data
handling).

It is certainly homebrew because the amount of time and effort I spent
in writing to code (and time to learn python on codeacademy - good site
BTW) was probably longer than I have spent designing and building
hardware.

Your mileage may vary....

Andy


I didn't know about these things. Pretty amazing. A UHF/VHF tuner for
under $10 on eBay. Which one do you have?


There are a number of similar ones. This is the one I have:

http://www.ebay.co.uk/itm/RTL2832U-R...em566780 9155

You need to make or buy an antenna connector so you can use a BNC or
something sensible to connect to your antenna system. The supplied
antenna is pretty grim, I suppose you could use the connector an snip
the rather poor coax short and put a decent connector on it.

Depending on which OS you use, there are a number of existing programs
you can use with it to get a feel for it before you start developing
your own. Some people use them with R Pi's to make receive only iGates
or Internet Scanners etc. I think I even saw a webpage where someone had
used one as a spectrum analyser.

My understanding was that the idea of using them as SDRs came from the
USA but perhaps not.

"Rambo" wrote in message
...
On Fri, 6 Mar 2015 09:47:07 -0000, "Jim GM4DHJ ..."
wrote:


"gareth" wrote in message
...
"rickman" wrote in message
...

Brian, Gareth is being nice, isn't saying anything stupid and so far
all
has been civil. You seem to be trying to find something to hit him
over
the head with. Please don't turn this into another argument with
him...

Well said, but not a problem here because both reay and cole, the
two perpetrators of unpleasantness are being widespreadly shunned and
are in my KF as I type.
(Note how quiet the unn.* NGs are since the start of the cole shunning!)


everybody would get on well if it wasn't for those two ........

Well just ignore their posts........

umur....

On 3/6/2015 10:21 AM, Brian Reay wrote:
On 06/03/2015 15:07, rickman wrote:
On 3/6/2015 2:46 AM, AndyW wrote:
On 05/03/2015 23:04, gareth wrote:
"Iain Young, G7III" wrote in message
...

An awful lot of evidence by citing off-the-shelf solutions for both
the hardware and the software of SDR.

It depends where you draw the line.
I have a DVB dongle that I use under linux.
I use pre-written drivers and a waterfall code module but the rest of
the code is self-written by me in c++ and python with some java 2D stuff
for the pretty front end and logging and analysis (largely because I
prefer the collections interface in Java over c++ for massive data
handling).

It is certainly homebrew because the amount of time and effort I spent
in writing to code (and time to learn python on codeacademy - good site
BTW) was probably longer than I have spent designing and building
hardware.

Your mileage may vary....

Andy


I didn't know about these things. Pretty amazing. A UHF/VHF tuner for
under $10 on eBay. Which one do you have?


There are a number of similar ones. This is the one I have:

http://www.ebay.co.uk/itm/RTL2832U-R...em566780 9155


You need to make or buy an antenna connector so you can use a BNC or
something sensible to connect to your antenna system. The supplied
antenna is pretty grim, I suppose you could use the connector an snip
the rather poor coax short and put a decent connector on it.

Depending on which OS you use, there are a number of existing programs
you can use with it to get a feel for it before you start developing
your own. Some people use them with R Pi's to make receive only iGates
or Internet Scanners etc. I think I even saw a webpage where someone had
used one as a spectrum analyser.

My understanding was that the idea of using them as SDRs came from the
USA but perhaps not.

What do you use yours for?

--

Rick

In message , Brian Reay writes
On 06/03/2015 13:32, Ian Jackson wrote:
In message , Charlie
writes
On Thu, 05 Mar 2015 22:01:39 +0000, Iain Young, G7III wrote:

A HF upverter added to the front end, and you are all set.

Very simple project, a cheap DIL crystal oscillator around 50MHz,
passive mixer with the ports switched around and you have a LF/MF/HF RX
from DC. Some front end filtering and Bob's your unc.

My first 2m QSO was made with a CB set feeding into a home-made
double-balanced diode mixer, and an ancient sig gen as the LO on 118 (or
maybe 177) MHz.

An interesting variation on the typical 28MHz 2m transverter. I'm a
bit surprised there were suitable CB sets around at the time I would
expect you to be starting our on 2m.

I'd always been an HF and (some 4m person), and I never had any 2m gear
until, by chance, I bought a Trio 2200 for £3 at a village car boot sale
(plus an Amstrad 901 CB that I also bought cost £5!). For my CB-to-2m
transversion, I was using my Fidelity 2000 (bought for £15 at another
village sale, for conversion to 10m).

I've never been keen on transverters myself. I still have a Microwave
Modules 2m 70 cm transverter somewhere, they were very popular in the
early 1980s or so. It worked well enough it was the need to keep
swapping things around I didn't like. Fine if you dedicate a radio for
use with the transverter but, in those days, I didn't have the luxury
of suitable radios to do that.

Yes, transverters can be a bit of fiddle. In the 70s, I made one to go
with my 80 to 10m gear (on 14MHz), to get on 160m. It worked OK, but it
was all a bit of a fiddle if I wanted to swap back and forth.




--
Ian

"rickman" wrote in message
...
Just as they feed the troll behavior in him, he feeds the troll behavior
in them.

I have no troll behaviour. I attempt to discuss the things and the ideas
that interest me but, unfortunately, a number of people, which figure
has included you, resort to abusive remarks in response to my attempts
to foment technical discussion.

On 06/03/2015 09:32, gareth wrote:
wrote in message
...


An AGC range of only 20dB?

You could cascade 2 of them, that would give you 23dB ;-)

Don't know to what you are replying, but one such biscuit as the RF
amplifier and a series of them in the IF chain would provide the
desired AGC range.

A good RF amplifier would make a poor IF amplifier.
A good IF amplifier would make a poor RF amplifier.

I fear that you are incorrect in your calculation, for 2 in series
with gains variable from 0 to 20 dB will give a range of 0 to 40 dB

(Think about it the other way around with resistive attenuators, and
what you get with 2 off 20dB attenuators in series)

I think Brian was taking the pi$$
(We all know these are voltage amps, so he meant 26dB :-))

On 06/03/15 15:29, rickman wrote:
On 3/6/2015 10:21 AM, Brian Reay wrote:
On 06/03/2015 15:07, rickman wrote:
On 3/6/2015 2:46 AM, AndyW wrote:
On 05/03/2015 23:04, gareth wrote:
"Iain Young, G7III" wrote in message
...

An awful lot of evidence by citing off-the-shelf solutions for both
the hardware and the software of SDR.

It depends where you draw the line.
I have a DVB dongle that I use under linux.
I use pre-written drivers and a waterfall code module but the rest of
the code is self-written by me in c++ and python with some java 2D
stuff
for the pretty front end and logging and analysis (largely because I
prefer the collections interface in Java over c++ for massive data
handling).

It is certainly homebrew because the amount of time and effort I spent
in writing to code (and time to learn python on codeacademy - good site
BTW) was probably longer than I have spent designing and building
hardware.

Your mileage may vary....

Andy


I didn't know about these things. Pretty amazing. A UHF/VHF tuner for
under $10 on eBay. Which one do you have?


There are a number of similar ones. This is the one I have:

http://www.ebay.co.uk/itm/RTL2832U-R...em566780 9155



You need to make or buy an antenna connector so you can use a BNC or
something sensible to connect to your antenna system. The supplied
antenna is pretty grim, I suppose you could use the connector an snip
the rather poor coax short and put a decent connector on it.

Depending on which OS you use, there are a number of existing programs
you can use with it to get a feel for it before you start developing
your own. Some people use them with R Pi's to make receive only iGates
or Internet Scanners etc. I think I even saw a webpage where someone had
used one as a spectrum analyser.

My understanding was that the idea of using them as SDRs came from the
USA but perhaps not.

What do you use yours for?


I've not used it much. I was curious and decided to try one. I don't
like radios you 'drive' from a keyboard or computer, I prefer the
traditional front panel.


The one exception is a PCR1000 which I use as a bit of test kit- with an
attenuator and suitable SW it makes a passable spectrum analyser. I may
try the RTL dongle out for this in time.

I do like the maths of SDRs etc. but actually using them holds little
attraction.


The same goes for modes like PSK etc.

I've no issue with others enjoying them, they just don't appeal to me.